Thin, flexible plastic films, such as Polypropylene, polyethylene, polyvinyl chloride, Tedlar.RTM. (a registered trademark of E.I. DuPont De Nemours & Co. for polyvinyl fluoride films), Mylar.RTM. (a registered trademark of E.I. DuPont De Nemours & Co. for polyester films), and similar impermeable, nonporous plastic films, have been found to be particularly useful as moisture, vapor and thermal barriers for a variety of products such as aircraft insulation blankets. These properties, especially thermal reflectance and decreased moisture transmission through the film, can be improved by providing a thin, reflective metallized layer, typically on one side of the plastic film.
Such films, however, require reinforcement to enable them to withstand manufacturing and subsequent use. Reinforcement is generally provided by bonding reinforcing fibers to the film.
One way of providing a reinforced film is to cast the molten film plastic onto a scrim or reinforcing fibers so that the reinforcing fibers are carried within the film itself. This method is disadvantageous, however, since it requires the manufacturer to acquire the equipment needed for casting and forming the various flexible plastic films and for metallizing if practical.
Another way of providing reinforced film is to select the desired pre-formed film or metallized film, and reinforce the film by adhesively bonding the reinforcing fibers or yarns to at least one side of the film.
Petroleum and organic based solvent adhesives have been widely used in the past to bond such reinforcing fibers to the film because of the speed of cure which is possible with such adhesives. However, the use of petroleum and organic based solvent adhesives is declining due to stricter air quality control laws. Further, solvent based adhesives may corrode aluminum, thus limiting the use of such reinforced films in aviation or in other environments in which aluminum is used. Thus, the need exists for a reinforced film in which the reinforcing yarns can be attached to the film using an adhesive which is non-corrosive and which produces low or no solvent emissions during cure.